[Chest wall mechanics in obstructive lung disease].

The effects of overinflation of the lung in obstructive lung disease on the function of chest wall (rib cage, diaphragm) were studied. Concerning the function of the rib cage, the lateral motion of the lower lateral rib cage was evaluated using several experimental models. The results showed that the lower lateral rib cage was moved by many factors, including the force of the diaphragm, rib cage, compliance of abdominal wall, zone of apposition and angle of the diaphragm at the part of its insertion into the rib cage with respect to the transverse section of the trunk. The inward motion of the lower lateral rib cage due to overinflation of the lung occurred by participation of these factors. Concerning the function of the diaphragm, the diaphragm at high lung volume in healthy subjects and patients with pulmonary emphysema was evaluated by the three-dimensional stereoscopic method. The radius of the portion of the dome in the diaphragm decreased at higher lung volume, and changes in lung volume at that lung volume were caused by changes in the shape in the posterior of the diaphragm.